The invention relates to a fluid adapter for a breathable gas delivery device, such as a facemask, for delivering breathable gas to a user.
When working in an environment in which the atmosphere is either contaminated or otherwise unsuitable for breathing it is necessary to use breathing apparatus. One option is to use self-contained breathing apparatus (SCBA) which typically comprises a cylinder of breathable gas that is carried by the user. Whilst this may be suitable for some applications, the equipment worn by the user may be bulky and may therefore restrict the activities that the user can carry out, and the size of the cylinder that the user can carry may not contain enough breathable gas for a suitable working duration.
It is therefore known for the breathable gas to be supplied to the wearer from a large cylinder that is either static or moveable on a trolley, or from a breathable gas airline installed within the building. The breathable gas is typically delivered to the user through a facemask or hood or protection suit that is fluidically connected to the source of breathable gas, such as a tank or airline, with a flexible conduit. The breathable gas may be supplied on demand, by using a lung demand valve for example, or may be supplied constantly.
If a constant flow breathable gas delivery device is used, such as a mask or hood, it may be desirable for the user to be able to inhale ambient air if possible so as to preserve the source of breathable gas; only using it when necessary. It may therefore desirable to provide an arrangement capable of achieving this both simply and effectively.